Reversible expansion means for interchangeable condenser and evaporator functions



sept. 24, 193s. ,s LQC'K 2,015,487 LE A REVERSIBLE EXPA TON MEANS RINTERCH EAB CONDEN AND PO OR FUNCTI S ed D 29, 1935 2 Sheets-Sheet 1 ler l l MIIB ,zo I

Sept. 24,-1935. A. s.l LOCKE 2,015,487 I -REVERSIBLE EXPANSION MEANS FORINTERCHANGEABLE CONDENSER AND EVAPORATOR FUNCTIONS.

` Filed Dec. 29, 1933 2 Sheets-Sheet 2 Patented Sept. l24, 1935 UNITEDSTATES REVERSIBLE EXPANSION MEANS' Fon INTERCHANGEABLE CONDENSER ANDEVAPORATOR FUNCTIONS Arthur S. Locke, Philadelphia, Pa., assgnor toBaldwin-Southwark Corporation, a corporation of Delaware ApplicationDecember 29, 1933, Serial No. 704,421

7- Glaims. (Cl. 62-l15) This invention relates to refrigerant expansionmeans and more particularlyto improved means whereby refrigerant mayflow :freely in one direction through the expansion mechanism but a willbe automatically restricted in its opposite direction of ow to effectthe expansion operation.

The lpresent invention is particularly adapted to refrigerating systemswherein the condenser and evaporator elements are adapted to have theirfunctions interchanged to permit the refrigerating system to be used forheating as well as cooling purposes. Such an interchangeable system isparticularly adapted for airconditioning units, especially of the roomtype employing complementar-y heat exchange elements of the aixcooledtype, wherein outside air is passed over one of said elements and roomair over the other.

It is one object of my invention to provide in an interchangeable systemof the foregoing type 1mproved refrigerant expansion means whereby therefrigerant may flow freely from one heat exchange element to the otherbut will be restricted during flow in the opposite direction, thereby toprovide the expansion' function. Another object in this respect is toprovide an improved means whereby the free ow and reverse restrictedflow is brought about automatically in response to the :dow ofrefrigerant in one direction or the other.

In one specific aspect of the invention I provide a oat actuatedvalve-controlled orifice in combination with means for freely bypassingrefrigerant around said orice in one direction of flow but whichautomatically closes said bypass in the opposite direction of ow so asto allow fluid ow only through the restricted orifice for expansionpurposes, a pair of the foregoing expansion devices being arranged inopposed seriesrelation whereby fluid expansion is effected in eitherdiiection of flow without undue restriction to the ow.

Other objects and advantages will be more apparent to those skilled inthe art from the follow- -ing description ofthe accompanying drawings inwhich:

Fig. l is a diagrammatic illustrationof an expansion system forinterchangeable complementary heat exchange elements embodying one formof my improved arrangement' Fig. 2 is an enlarged vertical section'through one ofthefloat controlled expansion devices;

Figs. 3 and 4 are arrangements similar to Fig. 1 but embodying modifiedforms of the bypassing action in combination with a float controlledexpansion means;

Fig. 5 is a diagrammatic view of means for interchanging the condenserand evaporator functions in combination with a compressor. 5

In the particular embodiments of the invention which are shown hereinmerely for the purpose of illustrating certain specific forms amongpossible others that the invention might take, I

.have disclosed in Fig. 1 a pair of complementary 10 heat exchangeelements I and! employed in a compressor-condenser-evaporator circuit.As shown in Fig. 5 the condenser and evaporator functions may beinterchanged merely by rotating valves 3 and 4 so as to connect thedischarge is 6^ of compressor 'I to one element and to connect thesuction side 8 to the other element or vice versa depending upon whichelement isto serve as a condenser or evaporator. Inasmuch as thecondenser and evaporator are preferably of the 20 -air cooled type, itis seen that outside air passing over the element serving as anevaporator will absorb heat from the outside atmosphere and transfer thesame to the element serving as the condenser over which room air wouldow. The 25 cooling operation of the unit causes the heat exchangeelement, say I, to serve as a condenser over which outside air flows tocool the same while the element 2 would function as the evaporatortocool the room air.

` To effectively permit this interchange of functions so that properexpansion of the fluid may be' had for either heat exchange elementdepending upon the direction of refrigerant ow therein, there isprovided a pair of traps 9 and 9. Each 35 of these traps is identical inconstruction and hence description of one will sumceforboth except thatit will be noted that they are interconnected by a pipe Il through thebottom thereof. The trap comprises', as shown more particularly 40 inFig. 2, a float IIJ having a closed upper end, except for small timingleak port I I', but open at its lower end. The pipe il projects upwardlythrough the lower open end of the trap and preferably into oat I0. Alever I2 is more or less 45 freely pivoted on a xed pin I3 carried bythe trap casing while the other end of said lever I2 is likewise pivotedto a hook I4 secured to the top of oat IU. A small ball valve I5 isslightly relatively movably supported on lever I2 so as to 50 properlyseat against an'expansion orifice I 6. This orice is formed centrally ofa check valve I1 normally resting on a seat I8 land provided with aseries of vertical flutes I9. Stop pins 2li are carried by` the trapcasingy and project beneath 55 check valve I1 but out of the path oflever I2. The trap is, ofcourse, connected as by a pipe 2| to itsl heatexchange element.

Operation-Assuming element I, of Fig. l, to be functioning as acondenser and element 2 as an evaporator, it is seen that the highpressure in condenser I will force check valve I1 downwardly againststop pins 20, thereby allowing free flow of refrigerant liquid 'throughflutes I9 to trap S- and thence down under and inwardly of the loweropen edge of fioat IU to pipe II from which it enters the other trap 9.As long as only liquid flows through pipe I I, this liquid will passbeneath the lower edge of float I0 of trap 9' and thence upwardlythrough its orifice I6 to the evaporator 2. The iioat ID of trap 9 willremain in its lower position due to its weight and due to the fact thatthe trap is entirely filled with` liquid. Also check valve I1 thereofwill remain closed` because of the high pressure on its under side andthe reduced pressure on its upper side. However, if the condenser is notcondensing refrigerant fast enough so that refrigerant gas flows throughtrap 9 over to trap 9', then the refrigerant gas will accumulate in theupper end of float I0 thereof and cause it to rise due to its lower endbeing sealed in liquid. This will cause ball I5 to seat against orificeI6 and temporarily prevent ow of refrigerant into the evaporator 2.However, the gas in the upper closed end of the float will graduallyleak through its port I I' and allow the fioat to lower by its ownweight. Thereupon more refrigerant will oW solely through expansionorice I6 to the evaporator, it being assumed that the size of port Il issuch that float I0 will be in its closed position long enough to permitmore refrigerant gas to 'be condensed in condenser I so that when trap 9does open only refrigerant liquid will ow over through pipe Il.

In the event that valves 2 and 3 are adjusted to interchange thefunctions of the heat exchange elements I and 2, then refrigerantcondensed in what is now the condenser 2 will create a high pressurey ontop of check valve I1 of trap 9 and cause thischeck valve to movedownwardly and thus permit free flow of refrigerant through its flutesI9 into trap 9' and thence in a left direction through pipe II to trap9. The high pressure in this trap 9 will cause its check I1 to close,thereby permitting refrigerant to pass only through the restrictedexpansion orifice I6. The oat for trap 9 will also function to controlthe refrigerant in the same manner as previously described for the otherdirection of flow.

From the foregoing disclosure it is seen that very effective means isprovided whereby a plurality of expansion orifices are alternativelyoperative automatically in accordance with the direction of refrigerantfiow through the system. Hence minimum resistance to the flow isobtained while at the same time maintaining complete expansionfunctions.

In the modification shown in Fig. 3 a separate check valve Ila isprovided in a pipe 25 leading from the header of heat exchange element Ito the fioat chamber of trap 9a while a similar check valve I1b isplaced in a pipe 26 connecting the header of the other heat exchangeelement 2 with the other trap 9a. In the modication of Fig. 4 opposedcheck valves I1'a and I1'b are disposed in a pipe 21 connected betweenthe traps 9b and Sb and their respective heat exchange elements. A pipe28 connects with pipe II and pipe 21 at a point between check valve I1'aand I1'b.

check valves I1a and I1b, or I1'a and I1'b, will bypass liquidrefrigerant around the expansion orifice of the respective trapsdepending upon which trap is functioning as the expansion element. Thecheck valves in all forms are in effect bypasses around the expansionorifices because in each case an additional passage area is openedsupplementary to the orifice passage. Hence it is seen that a relativelysimple and yet very effective means is provided in all forms forinsuring maximum efiiciency in the uid ow together with elimination ofany possibility of a double expansion action such as might take place incase the flow had to pass through both expansion orifices.

It will of course be understood that various changes in details ofconstruction and arrangement of parts may be made by those skilled inthe art without departing from the spirit of the invention as set forthin the appended claims.

I claim: y

l. A refrigerating system comprising, in combination, a pair ofcomplementary heat exchange elements, a plurality of refrigerantexpansion devices, one for each of said heat exchange elements, saiddevices having provision whereby they are alternatively operative toallow free flow of refrigerant through one and restricted ow through theother automatically in accordance with the direction of refrigerant flowfrom one heat exchange element to the other element.

2. A refrigerating system comprising, in combination, a pair ofcomplementaryheat exchange elements adapted to have their condenser andevaporator functions interchanged whereby the refrigerant flows from oneelement to the other or vice versa, refrigerant expansion mechanisms oneassociated with each of said heat exchange elements, and check valvesassociated with each expansion mechanism to permit free flow ofrefrigerant in one direction through one of said mechanisms butrestricted flow through the other mechanism or vice versa automaticallyin accordance with the direction of refrigerant flow through said heatexchange elements.

3. A refrigerating system comprising, in combination, a pair ofcomplementary heat exchange elements adapted to have their condenser andevaporator functions interchanged whereby the refrigerant flows from oneelement to the other or vice versa, a pair of series connected floatoperated expansion means one for each of said heat exchange elements,each of said expansion means having a check valve controlled passage topermit free flow of refrigerant therethrough in one direction but toprevent flow in the reverse direction.

4. A refrigerating system comprising, in combination. a pair ofcomplementary heat exchange elements adap-ted to have their condenserand evaporator functions interchanged whereby the refrigerant flows fromone-element to the other or vice versa, expansion means associated withsaid heat exchange elements including a float controlled expansionorifice, and means automatically responsive to reverse ow through saidexpansion means for bypassing refrigerant freely around said orifice.

5. A refrigerating system comprising, in combination, a pair ofcomplementary heat exchange elements adapted to have their condenser andevaporator functions interchanged whereby the refrigerant flows from oneelement to the other or vice versa, a float trap having an expansion uorifice associated with said heat exchange elements, and a check valveadapted to be opened or closed by high and low condenser and evaporatorpressures in said heat exchange elements thereby to effect refrigerantexpansion in only one direction of flow through said trap but to permit-free flow therethrough in the opposite direction.

6. A refrigerating system comprising, in combination, a pair ofcomplementary heat exchange elements adapted to have their condenser andevaporator functions interchanged whereby the refrigerant flows from oneelement to the other or vice versa, means providing an expansionorifice, a float actuated valve for controlling said orice, and a checkvalve in which said expansion orifice is formed. e Y

7. A refrigerating system comprising, in combination, a pair ofcomplementary heat exchange elements adapted to have their condenser andevaporator functions interchanged whereby the refrigerant iows from oneelement to the other or vice versa, a pair of series connected expansiondevices one associated with each of said heat exchange elements, and acheck valve controlled passage adapted to bypass refrigerant around onevor the other of said expansion devices automatically in accordance withthe direction of 4refrigerant iiow therethrough.

ARTHUR S. LOCKE. 15

